The present inventor has already invented an insulating wall element in the form of a plate for covering a floor or a ceiling, as disclosed in Document FR-A-2 637 887. That wall element comprises a layer of insulating material having projections on one face and a layer of covering material that covers the layer of insulating material. The projections leave passages in which it is possible to establish a flow of fluid for the purposes of heating, cooling, drying, or humidifying the premises, or else to lay pipework for gas, water, electricity, etc. That wall element provides an insulating effect not only thermally, but also acoustically.